laminar flow cabinet

The production of air purification: the production environment where the air is filtered** was first used by the aerospace industry. Even an extremely small defect can cause satellite work errors. Therefore, the US ** Aerospace Center and its service providers built a workshop with a filter ceiling interlayer and a filter wall. Moreover, it has created many basic pollution control concepts, including management methods from staff clean clothes to clean room objects.
The semiconductor industry has adopted many technologies in this area. However, a major problem is that it is difficult to maintain its inherent cleanliness when expanding from a small processing workshop to a large workshop with more workers. The early semiconductor industry evolved the method of filtering ceiling interlayers and walls into ultra-clean workbenches. This is mainly to install the air filter on a single workbench and use non-shedding materials. Outside of the ultra-clean workbench, the wafers are stored and transported in sealed boxes.
In a large workshop, the ultra-clean workbenches arranged in sequence form a processing area, so that the wafers pass through in the process sequence without being exposed to the air. The filter of the ultra-clean workbench is a high-efficiency particle collection filter (high-efficiency filter). These filters are composed of brittle fibers (fiber) with many small holes and folded according to the accordion leaf. Due to the high density (unit: g/cm3 or kg/m3) of small holes and the large area of the filter layer, a large amount of The air flows at a low speed. Because the low-speed air can avoid air flow, it is beneficial to the cleanliness of the workbench, and it is also necessary for the operation controller to work in a comfortable environment. A typical air flow rate 6 is 90 to 100 inches per minute. The high-efficiency filter can achieve a filtration efficiency of 99.99% or higher, and can be used in three purification methods.

Ultra-close table structure


Generally speaking, the HEPA high-efficiency (referring to high-efficiency) filter is installed on the top of the ultra-clean workbench. The ultra-clean workbench is designed to meet the cleanliness requirements of the local working area in the modern industry, optoelectronic industry, bio-pharmaceutical, scientific research and testing. The air is sucked in by the fan, first passes through the pre-filter, and then through the HEPA high-efficiency filter, and flows out in a uniform and parallel manner, changing its direction on the surface of the worktable and flowing out of the worktable. The baffle plate can be installed to control the direction of air flow on the surface of the wafer. This method is usually called a vertical laminar air flow (VLF) ultra-clean table, which is named by the direction of air flow.
Some ultra-clean workbenches install HEPA high-efficiency (referring to high-efficiency) filters at the back of the workbench. This method is called a laminar air flow parallel ultra-clean workbench.
No matter what type of ultra-clean workbench, it is inseparable from the use of HEPA high-efficiency filter. It is no exaggeration to say: without high-efficiency filter, the ultra-clean workbench will not meet its purification requirements.